The sfc scannow option is one of several specific switches available in the sfc command, the Command Prompt command used to run System File Checker.
While there are plenty of different things you can do with the command, sfc /scannow is the most common way that the sfc command is used.
sfc /scannow will inspect all of the important Windows files on your computer, including Windows DLL files. If System File Checker finds an issue with any of these protected files, it will replace it.
Follow these steps for using sfc with the scannow option to repair important Windows files:
Time Required: Using sfc /scannow to repair important Windows files usually takes 5 to 15 minutes.
How To Use SFC /Scannow
Open Command Prompt as an administrator, very often referred to as an “elevated” Command Prompt.
Important: For the sfc /scannow command to work properly, it must be executed from an elevated Command Prompt window in Windows 10, Windows 8, Windows 7 and Windows Vista. This is not required in previous versions of Windows.
